This invention relates to subsea well equipment, and more particularly to equipment, referred to as tieback connectors, used to interconnect well conductor or riser pipe with a wellhead beneath the water surface.
For many years the petroleum industry has been producing oil and gas from offshore wells wherein the wellhead is located underwater, i.e. subsea, and the Christmas tree is positioned on a platform or other surface facility. Extending between these subsea wellheads and their surface trees are relatively large diameter conductor or riser pipes that are attached to the wellhead housings by tieback connectors that require rotation of a pipe string to lock them to, and release them from, the housings. Although right-hand rotation of the pipe string during the locking procedure usually presents no problem, when the string is rotated to the left to unlock the connector the joints in the string can unthread, and reconnecting those joints presents a serious and costly problem to the operator.